An efficient method for inverse dynamics of kinematically defective parallel platforms

Abstract

AbstractIn addition the general six‐degree‐of‐freedom parallel platforms, parallel platforms with fewer than six DOF can also be used in the structural design of robotic manipulators. The common property of these parallel platforms is that the motion parameters used to describe the position and orientation of the movable platform are six, but fewer than six are independent. In their general configurations, arbitrary six‐dimensional motion of the platform cannot be achieved by the actuators mounted on the legs, therefore they are kinematically defective. Because of this defect, the inverse dynamic analysis method, which is applicable to the general six‐DOF parallel platforms, cannot be directly used for the kinematically defective parallel platforms (KDPPs). In this paper, an effective method for formulating the inverse dynamics of KDPPs is presented. Using the proposed method, three different KDPPs are studied and their inverse dynamic formulas are derived. © 2002 John Wiley & Sons, Inc.